1. Field of the Invention
The present invention relates to a set for producing at least one temporary tooth crown or bridge, having a carrier for accommodating a crown and bridge material in an amount that is at least sufficient for the production of a tooth crown.
2. The Prior Art
In dental medicine, such temporaries are used to protect the soft tissue of the tooth (pulpa) from thermal, chemical, and bacterial influences, after the tooth has been prepared, i.e. ground down for the production of crowns or bridges. Furthermore, these temporaries serve a variety of functions. They maintain chewing function, fix the occlusal and/or sagittal jaw relationships in place, and they prevent the adjacent mucous membrane from growing onto the tooth stump. In the front tooth sector, in particular, such temporaries also fulfill esthetic and phonetic functions.
For the production of a temporary crown or bridge, an impression of the existing tooth situation is generally taken before preparation. After preparation of the tooth or teeth, the situation impression is then filled with an autopolymerizable temporary crown and bridge material, in the places of the prepared teeth. The filled impression is then repositioned on the prepared tooth stumps, and the temporary crown and bridge material is cured in the mouth, until an elastic phase has been reached. During this elastic phase, the material is removed and worked on, if necessary, before it is cured, either within the mouth, or outside of the mouth, with additional heating, for example. Such a material is described in EP 1 173 137 B1, for example.
During final curing outside of the mouth, the temporary crown or bridge shrinks, whereby the lumen formed in the temporary crown or bridge by means of the prepared tooth stump also shrinks. As a result, it is frequently necessary to enlarge the lumen of the temporary crown or bridge before attaching it to the prepared tooth stump. For example, the lumen of the temporary crown or bridge may be enlarged by grinding it down. Furthermore, it takes a comparatively long time until such autopolymerizing temporary crowns or bridges have reached their final technical properties, so that they can be subjected to full chewing stress. As a result, not only is the treatment time increased, but also the patient cannot put full stress on the temporary crown or bridge for at least several hours afterwards.
In EP 0 897 710 B1, a light-induced cationically curing composition is proposed, which can be used for plastics for temporaries or for prosthetic teeth. This composition contains camphor quinone and aromatic amines as initiators, for example. Furthermore, a light-curing plastic for temporary crowns and bridges is known under the designation “GC REVOTEK LC” from the company GC GERMANY GmbH. This material has a putty-like (putty) consistency. In producing a temporary crown or bridge, the material is first manually pre-shaped outside the mouth, then applied to the prepared tooth stump, and there roughly shaped by having the patient bite down on the material. After a first curing step using a light-curing lamp, the roughly shaped temporary crown or bridge is removed from the patient's mouth and cured further by applying more light extraorally. Subsequently, the shape is corrected with a polisher.
Although this method is particularly labor-intensive for the dentist, the temporary crowns or bridges obtained in this manner provide only an insufficient reproduction of the original tooth situation. Such temporary crowns or bridges therefore feel uncomfortable in the mouth. Furthermore, the production of a temporary crown or bridge with a putty-like material is disadvantageous, since its flow properties are insufficient, so that the material does not optimally adapt to the tooth contours. When these known materials are used in an impression, there is the risk that the impression will be plastically or elastically deformed due to straining, so that again, only an insufficient reproduction of the original tooth situation is possible.
Furthermore, there are two-component systems and dual-curing two-component systems that cure purely chemically, such as LUXATEMP® SOLAR, a temporary dental material from the company DMG, or PROVIPONT®, a temporary dental material from the company Vivadent Ivoclar, which can be additionally cured by supplying light, after chemical curing. These two-component systems must be precisely metered and mixed well with one another before use, because otherwise, curing is negatively influenced. Therefore such two-component systems are often perceived as being disadvantageous.
Fundamentally, it is difficult for a dentist, when using the known materials for temporary crowns or bridges, to remove them from the mouth after the first adaptation on the prepared tooth stump, at the right moment so that they can be worked. In the case of chemical curing initiated by mixing a base component with a catalyst component, this curing process proceeds continuously. In this connection, the temporary crown or bridge must remain in the patient's mouth until it can be removed in one piece, without tearing or undergoing any other plastic deformations. At the same time, excess amounts of the material, which have run into undercuts, for example (e.g. interstices between the teeth), must still be elastically deformable. Otherwise, the temporary can be removed only with difficulty after it has cured completely. In autopolymerizing systems, the right point in time for first removal of the temporary and subsequent finishing cannot be clearly determined.
For the production of a quickly curing impression, a transparent impression tray is proposed in U.S. Pat. No. 4,867,682, which is filled with an impression material that can be polymerized by means of light. This light-polymerizing impression material has the elasticity required for impression materials after final curing, in order to guarantee easy removal from the mouth. In contrast, significantly greater values for modulus of elasticity and bending strength are required for a temporary crown and bridge material. The known light-polymerizing impression material is consequently completely unsuitable for use as a crown and bridge material (compare ISO 4823 for impression materials and ISO 10477 for crown and bridge materials). Furthermore, in EP 0 522 341, a transparent material is described that has great hardness and low elastic deformation, for the production of a bite registration. This material is completely unsuitable as an impression material, because of its great hardness.